docs: def on_delivery(self, channel, method, properties, body):
          """Invoked by pika when RabbitMQ delivers a message from a queue.
  
          :param channel: The channel the message was delivered on
          :type channel: pika.channel.Channel
          :param method: The AMQP method frame
          :type method: pika.frame.Frame
          :param properties: The AMQP message properties
          :type properties: pika.spec.Basic.Properties
          :param bytes body: The message body
  
          """
          self.callbacks.on_delivery(
              self.name, channel, method, properties, body)